1. Field of the Invention
The present invention relates to a rotating device having a shaft fixed to a fixing body.
2. Description of the Related Art
Disk drive devices like a hard disk drive are becoming compact and increasing the capacity thereof, and are built in various electronic devices. Such disk drive devices are popularly built in, in particular, portable electronic devices, such as a laptop computer and a portable music player. The disk drive devices built in such portable electronic devices require improved shock resistance and vibration resistance so as to withstand a shock due to falling and a vibration when carried in comparison with disk drive devices built in stationary electronic devices like a desktop computer.
For example, JP 2009-162246 A and JP 2010-127448 A disclose a motor which has a shaft fixed to a base plate and which also has a bearing that is a fluid dynamic bearing mechanism.
According to the conventional fixed-shaft motor disclosed in JP 2009-162246 A and JP 2010-127448 A, a dynamic pressure generator is formed in the direction of a rotational axis R so as to be held between two tapered seals. According to this configuration, if there is a limitation for the thickness of the motor, it is necessary to reduce the dimension of the dynamic pressure generator in the direction of the rotational axis R. This reduces the rigidity of the bearing, which negatively affects the shock resistance and vibration resistance of the motor. Moreover, such a motor has a fixing body and a rotating body, and when receives a shock like falling, the surface of the fixing body and that of the rotating body in the direction of the rotational axis R may contact with each other. The contact of the rotating body with the fixing body may result in a cause of breakdown in the worst case.
Furthermore, according to such a motor, it is necessary to reduce the dimension of the tapered seal in the direction of the rotational axis R. In this case, if a clearance in the radial direction is increased to maintain the lubricant retaining amount by the tapered seal, capillary force becomes weak. When the capillary force by the tapered seal decreases, the lubricant often leaks.
Such a technical issue is not only for the motors but also for other kinds of rotating devices, in particular, rotating devices having a shaft fixed to a fixing body and also having a fluid dynamic bearing.
The present invention has been made in view of such a circumstance, and it is an object of the present invention to provide a rotating device that has an increased rigidity of a bearing or is capable of reducing the leak-out of a lubricant.